autoip.h

00001 /**
00002  * @file
00003  *
00004  * AutoIP Automatic LinkLocal IP Configuration
00005  */
00006 
00007 /*
00008  *
00009  * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
00010  * All rights reserved.
00011  *
00012  * Redistribution and use in source and binary forms, with or without modification,
00013  * are permitted provided that the following conditions are met:
00014  *
00015  * 1. Redistributions of source code must retain the above copyright notice,
00016  *    this list of conditions and the following disclaimer.
00017  * 2. Redistributions in binary form must reproduce the above copyright notice,
00018  *    this list of conditions and the following disclaimer in the documentation
00019  *    and/or other materials provided with the distribution.
00020  * 3. The name of the author may not be used to endorse or promote products
00021  *    derived from this software without specific prior written permission.
00022  *
00023  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
00024  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
00025  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
00026  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00027  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
00028  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00029  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00030  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
00031  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
00032  * OF SUCH DAMAGE.
00033  *
00034  * Author: Dominik Spies <kontakt@dspies.de>
00035  *
00036  * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
00037  * with RFC 3927.
00038  *
00039  *
00040  * Please coordinate changes and requests with Dominik Spies
00041  * <kontakt@dspies.de>
00042  */
00043  
00044 #ifndef __LWIP_AUTOIP_H__
00045 #define __LWIP_AUTOIP_H__
00046 
00047 #include "lwip/opt.h"
00048 
00049 #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
00050 
00051 #include "lwip/netif.h"
00052 #include "lwip/udp.h"
00053 #include "netif/etharp.h"
00054 
00055 #ifdef __cplusplus
00056 extern "C" {
00057 #endif
00058 
00059 /* AutoIP Timing */
00060 #define AUTOIP_TMR_INTERVAL      100
00061 #define AUTOIP_TICKS_PER_SECOND (1000 / AUTOIP_TMR_INTERVAL)
00062 
00063 /* RFC 3927 Constants */
00064 #define PROBE_WAIT               1   /* second   (initial random delay)                 */
00065 #define PROBE_MIN                1   /* second   (minimum delay till repeated probe)    */
00066 #define PROBE_MAX                2   /* seconds  (maximum delay till repeated probe)    */
00067 #define PROBE_NUM                3   /*          (number of probe packets)              */
00068 #define ANNOUNCE_NUM             2   /*          (number of announcement packets)       */
00069 #define ANNOUNCE_INTERVAL        2   /* seconds  (time between announcement packets)    */
00070 #define ANNOUNCE_WAIT            2   /* seconds  (delay before announcing)              */
00071 #define MAX_CONFLICTS            10  /*          (max conflicts before rate limiting)   */
00072 #define RATE_LIMIT_INTERVAL      60  /* seconds  (delay between successive attempts)    */
00073 #define DEFEND_INTERVAL          10  /* seconds  (min. wait between defensive ARPs)     */
00074 
00075 /* AutoIP client states */
00076 #define AUTOIP_STATE_OFF         0
00077 #define AUTOIP_STATE_PROBING     1
00078 #define AUTOIP_STATE_ANNOUNCING  2
00079 #define AUTOIP_STATE_BOUND       3
00080 
00081 struct autoip
00082 {
00083   ip_addr_t llipaddr;  /* the currently selected, probed, announced or used LL IP-Address */
00084   u8_t state;               /* current AutoIP state machine state */
00085   u8_t sent_num;            /* sent number of probes or announces, dependent on state */
00086   u16_t ttw;                /* ticks to wait, tick is AUTOIP_TMR_INTERVAL long */
00087   u8_t lastconflict;        /* ticks until a conflict can be solved by defending */
00088   u8_t tried_llipaddr;      /* total number of probed/used Link Local IP-Addresses */
00089 };
00090 
00091 
00092 /** Init srand, has to be called before entering mainloop */
00093 void autoip_init(void);
00094 
00095 /** Set a struct autoip allocated by the application to work with */
00096 void autoip_set_struct(struct netif *netif, struct autoip *autoip);
00097 
00098 /** Start AutoIP client */
00099 err_t autoip_start(struct netif *netif);
00100 
00101 /** Stop AutoIP client */
00102 err_t autoip_stop(struct netif *netif);
00103 
00104 /** Handles every incoming ARP Packet, called by etharp_arp_input */
00105 void autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr);
00106 
00107 /** Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds */
00108 void autoip_tmr(void);
00109 
00110 /** Handle a possible change in the network configuration */
00111 void autoip_network_changed(struct netif *netif);
00112 
00113 #ifdef __cplusplus
00114 }
00115 #endif
00116 
00117 #endif /* LWIP_AUTOIP */
00118 
00119 #endif /* __LWIP_AUTOIP_H__ */